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Cohort participation and retention

Timeline of surveys since 1996

Cohort1989-951973-781946-511921-26
Survey 1Year (age range)2013 (18-23)1996 (18-23)1996 (45-50)1996 (70-75)
Respondents (N)17010142471371412432
Survey 2Year (age range)2014 (19-24)2000 (22-27)1998 (47-52)1999 (73-78)
Respondents (N)1134496881233810434
Survey 3Year (age range)2015 (20-25)2003 (25-30)2001 (50-55)2002 (76-81)
Respondents (N)89619081112268646
Survey 4Year (age range)2016 (21-26)2006 (28-33)2004 (53-58)2005 (79-84)
Respondents (N)90079145109057158
Survey 5Year (age range)2017 (22-27)2009 (31-36)2007 (56-61)2008 (82-87)
Respondents (N)84958199106385560
Survey 6Year (age range)2019 (24-29)2012 (34-39)2010 (59-64)2011 (85-90)
Respondents (N)83468009100114055
Survey 7Year (age range)2023 (28-33)2015 (37-42)2013 (62-67)Surveyed at six
monthly intervals
from November 2011
(see next table)
Respondents (N)in progress71869151
Survey 8Year (age range)2018 (40-45)2016 (65-70)
Respondents (N)71218622
Survey 9Year (age range)2021 (43-49*)2019 (68-73)
Respondents (N)68757956
Survey 10Year (age range)2022 (71-77)
Respondents (N)7159
This table shows the number of participants for each survey, completed by each Study cohort.
Data known as at 7th May 2024.

*This is more than the usual 5 year age range because the survey was open for 17 months due to COVID-19.

1921-26 Cohort: number of respondents for each six-monthly follow up (6MF)

SurveyTotal (N)Year submitted:2011201220132014201520162017201820192020202120222023
Age range (years):85-9086-9187-9288-9389-9490-9591-9692-9893-9994-10095-10196-10297-103
6MF1385528299455913241200000
6MF233953069248451481531100
6MF32993165111789633168641000
6MF426232216292572781254200
6MF52311921116913341161377310
6MF620321591299643318118530
6MF71780595985110352989630
6MF8155611293115228179730
6MF9137643973713333149650
6MF101215823285552317750
6MF1110642606121244415522
6MF129115692525422860
6MF1377816047796231930
6MF146734131943817101
6MF155551163297124132
6MF1646127413934122
6MF173747922451155
6MF18304170103274
6MF1924243155431
6MF201921106913
6MF21137269120
6MF22855629
6MF2330822
From November 2011, shorter surveys containing a set of core questions were mailed to the 1921-26 cohort every six months after the return of the previous survey.
This six monthly survey has no finish date and therefore we continue to receive surveys for each wave.
Each row shows the total number of respondents, followed by the number of responses made each year, for each individual wave.